元坝气田长兴组生物礁高含硫底水气藏稳产中后期精准挖潜关键技术  

Key technologies for accurate potential tapping in the mid-to-late stage of stable production of Changxing Formation bioherm high-sulfur gas reservoirs with bottom water in the Yuanba Gas Field,Sichuan Basin

作　　者：郭彤楼[1] 祝浪涛 刘殷韬[1] GUO Tonglou;ZHU Langtao;LIU Yintao(Sinopec Southwest Oil&Gas Company,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石化西南油气分公司,四川成都610041

出　　处：《天然气工业》2024年第11期72-81,共10页Natural Gas Industry

基　　金：中国石化科技部重点项目“高含硫复杂生物礁底水气藏稳产关键技术研究”(编号:P21025)。

摘　　要：四川盆地元坝气田长兴组生物礁高含硫底水气藏埋深近7000 m,剩余天然气潜力区普遍具有礁体小、储层薄、非均质性强、气水关系复杂、直井产量低等特点,气藏稳产中后期天然气挖潜面临剩余潜力精准预测难度大,超深水平井安全钻井与气井达产风险高等难题。为此,梳理了元坝气田开展挖潜调整以来在高产富集主控因素分析、礁体与储层连通性评价、隔层与渗流通道精细表征、挖潜对策与配套技术研发等方面取得的进展,形成了适用于气田稳产中后期精准挖潜关键技术。研究结果表明:①高产井大多位于构造高部位、生物礁礁顶储层内,礁体与储层发育状况、隔层与渗流通道发育状况、礁体间储层连通性对未动用储量与剩余气分布及开发潜力评价影响较大;②将储层与隔层渗透率比值K_(r)/K_(l)=60和K_(r)/K_(l)=150作为隔夹层类型划分的阈值,可将该区隔夹层划分为致密型、弱渗透型及高渗透型3种类型,高渗透型隔夹层K_(r)/K_(l)<60,对地层水封隔能力弱;③采用流动单元指数(Ifz)可将储层大致分为4个类型,当渗流通道Ifz<2.47时,渗透能力小,可以视为隔夹层;④评价礁体间的连通性关键取决于礁间是否有储层及礁间储层的渗透率级差,当礁间不发育储层,则连通性取决于礁间储层的启动压力梯度与气井生产压差。结论认为:①以礁体发育规模、隔层与渗流通道发育情况、储层连通性及气水分布作为剩余气潜力评价标准对所有潜力区进行分级,优选部署新井、原井眼侧钻、老井挖潜等动用对策及相应的工艺技术,可实现潜力区储量的效益动用;②精准挖潜关键技术已应用于元坝气田天然气挖潜,已实施的8口调整及挖潜井效果显著,配产超过260×10^(4)m^(3)/d,累计产气量超过30×10^(8)m^(3)。该技术对于同类气藏的高效开发具有重要的指导和借鉴意义。The Changxing Formation bioherm high-sulfur gas reservoirs with bottom water in the Yuanba Gas Field of the Sichuan Basin are buried at nearly 7000 m,and correspond to remaining gas potential areas generally characterized by small reef bodies,thin beds,strong heterogeneity,complex gas-water relationships,and low production of vertical wells.These characteristics pose challenges to the accurate prediction of remaining potential in the mid-to-late stage of stable production of the gas reservoir,and threaten the safe drilling of ultra-deep horizontal wells and the expected production of gas wells.This paper reviews the progress made in the Yuanba Gas Field since the adjustment of its potential tapping in terms of main controlling factors of high yield and enrichment,evaluation of reef–reservoir connectivity,fine characterization of barriers and flow channels,and potential tapping strategies and supporting technologies.The key technologies suitable for the accurate potential tapping in the mid-to-late stage of stable production of gas field are developed.The following results are obtained.First,high-yield wells are mostly located at structural highs or at the top of bioherm.The development situations of reef bodies,reservoirs,barriers and flow channels and the inter-reef reservoir connectivity have significant impacts on the distribution and development potential evaluation of non-producing reserves and remaining gas.Second,if the permeability ratio of the reservoir to the barrier,K_(r)/K_(l)=60 and K_(r)/K_(l)=150,is taken as the threshold of barrier for water isolation,the barriers in this area can be classified into three types:tight,weakly permeable,and highly permeable.The highly permeable barrier has a K_(r)/K_(l)<60,indicating a weak ability to isolate formation water.Third,by virtue of the flow unit index Ifz,the reservoirs can be roughly classified into four types.The reservoir with Ifz<2.47,indicating a low permeability,is considered as a barrier.Fourth,the key to evaluating the connectivity between reef

关 键 词：元坝气田 长兴组 生物礁底水气藏 高产稳产 隔夹层 渗流通道 连通性 挖潜对策 

分 类 号：TE37[石油与天然气工程—油气田开发工程]